Nitrosyl Heme Complexes. ESR Spectral Simulation of Internal Rotation of Axial Ligand.

亚硝酰血红素复合物。

基本信息

批准号：
10672027
负责人：
SATO Mitsuo
金额：
$ 2.05万
依托单位：
Teikyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10672027/
关键词：
Nitrosyl heme complex ESR of nitrosyl heme Internal rotation of axial ligand ^<57>Fe hyperfine splitting Stochastic Liouville method Temperature dependent ESR spectrum

项目摘要

ESR spectra of 5-coordinate nitrosyl heme complex, Fe (TMP) NO, have been meaured in toluene in the temperature range between 10 and 380 K, where TMP is tetramesitylporphyrin. The spectra showed a drastic change from rhombic symmetry (g_1≠g_2≠g_3) at lower temperatures (10〜120 K) to axial one (g_3≠g_1=g_2≡g_⊥) at intermediate temperatures (120〜200 K) and to isotropic one (g_1=g_2=g_3≡g_0) at higher temperatures (220-380 K). Hyperfine splitting constants due to the ^<57>Fe nucleus (I=1/2) were determined in units of 10^<-4> cm^<-1> as |A_1|=11.3, |A_2|=9.5, |A_3|=6.6, |A_⊥|=9.5, |a_0|=5.2, with the positive sign for the A_3 constant and the negative one for the others. The observed spectra are simulated using the stochastic Liouville method. The temperature dependent spectra have been interpreted in terms of the 90° jump-internal-rotation (R_2) of axially coordinated nitrosyl ligand in addition to the Brownian rotational motion (R_1) of the nitrosyl heme complex. Both the rates of R_1 and R_2 are fast enough at higher temperatures to average out the magnetic anisotropies. R_1 becomes slower with decreasing temperature and is essentially frozen near 200 K, while the rate of R_2 is so fast above 120 K to average out the g_1, g_2 anisotropy and is still fast above 40 K to cause the extra peaks near(g_1+g_2)/2, which characterizes the 90° jump-internal-rotation of axially coordinated nitrosyl ligand.

5坐标亚硝基血红素复合物的ESR光谱，Fe（TMP）NO，在甲苯中的温度范围为10至380 K的甲苯中，其中TMP为Tetamesitylporphyrin。光谱显示在较低温度（10至120 K）上从菱形对称性（g_1≠g_2≠g_3）变化到中等温度（120至200 k）和同位素的一个（G_1 = g_1 = g_1 = g_2 = g_2 = g_2 = g_2 = g_2 = g_3周），在轴向一（g_3≠g_3≠g_1 = g_1 = g_2g_⊥）上。 Hyperfine splitting constants due to the ^<57>Fe nucleus (I=1/2) were determined in units of 10^<-4> cm^<-1> as |A_1|=11.3, |A_2|=9.5, |A_3|=6.6, |A_⊥|=9.5, |a_0|=5.2, with the positive sign for the A_3 constant and the negative one for the others.使用随机Liouville方法模拟观察到的光谱。除了硝基基血红素复合物的布朗旋转运动（R_1）外，还用轴向配位的硝基配体的90°跳跃内部旋转（R_2）来解释温度依赖光谱。 R_1和R_2的速率在较高的温度下都足够快，可以平均消除磁动率。 R_1 becomes slower with decreasing temperature and is essentially frozen near 200 K, while the rate of R_2 is so fast above 120 K to average out the g_1, g_2 anisotropy and is still fast above 40 K to cause the extra peaks near(g_1+g_2)/2, which characterizes the 90° jump-internal-rotation of axially coordinated nitrosyl ligand.